Abstract
The airwave effect greatly influences the observational data from controlledsource electromagnetic exploration in shallow seas, which obscures the abnormal effects generated by exploration targets and, hence, affects the accuracy of the late exploration data interpretation. In this study, we propose a method to separate the main part from the anomalous field of marine controlled-source electromagnetic method (MCSEM) data based on Stratton–Chu integral transforms to eliminate the airwave effect, which dominates observed electromagnetic (EM) response in shallow seawater. This method of separating the main part from the anomalous field is a type of finite impulse response filter based on a discrete data set. Theoretical analysis proved that the method is stable and able to effectively depress noise. A numerical test indicated that the method could successfully eliminate the airwave effect from the observed EM signals generated by an air–water interface and a seawater layer. This technique is applicable for seawater models with either flat or rough seabeds.
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Acknowledgments
The foundation work of this study was completed at the University of Utah, U.S.A., and the authors sincerely thank Professor Zhdanov for his careful guidance.
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Research supported by the National Natural Science Foundation of China (No. 41574067) and 863 Program (No. 2012AA09A404).
Professor Wang Shu-Ming received his Ph.D. from the China University of Geosciences, Wuhan, in 2002. He is now working at the Institute of Geophysics and Geomatics, China University of Geosciences. He worked as a senior researcher in the Department of at the University of Utah from 2006 to 2010, and in the Mobile station for post-doctors at the China University of Geosciences, from 2002 to 2004. His main research interests are electromagnetic data processing, and forward and inverse calculation.
Corresponding author: Di Qing-Yun, senior researcher, received her Ph.D. from the Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, in 1998. She is now working at the Institute of Geology and Geophysics, Chinese Academy of Sciences, mainly focusing on research and the application of electromagnetics for exploration.
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Wang, SM., Di, QY., Wang, R. et al. Removal of the airwave effect by main-part decomposition of the anomalous field of MCSEM data. Appl. Geophys. 15, 3–10 (2018). https://doi.org/10.1007/s11770-018-0653-1
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DOI: https://doi.org/10.1007/s11770-018-0653-1